refactor: remove some deps on lru

[BugenZhao]

I hereby agree to the terms of the RisingWave Labs, Inc. Contributor License Agreement.

What's changed and what's your intention?

As title.

Checklist

• I have written necessary rustdoc comments.
• I have added necessary unit tests and integration tests.
• I have added test labels as necessary.
• I have added fuzzing tests or opened an issue to track them.
• My PR contains breaking changes.
• My PR changes performance-critical code, so I will run (micro) benchmarks and present the results.
• I have checked the Release Timeline and Currently Supported Versions to determine which release branches I need to cherry-pick this PR into.

Documentation

• My PR needs documentation updates.

Release note

[BugenZhao]

• refactor:  remove some deps on lru #23489 👈 (View in Graphite)
• chore: remove local_stats_alloc #23488
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[Copilot]

Pull Request Overview

This PR refactors the codebase to remove dependencies on the lru crate by replacing LRU cache implementations with simpler alternatives. The main change is replacing an LRU cache-based SetStmts implementation with an IndexMap-based solution, and consolidating indexmap dependency versions across the workspace.

Key changes:

• Replaced LruCache with IndexMap in the simulation test client's SetStmts struct
• Removed the lru dependency from production code crates (stream, common)
• Standardized indexmap dependency version across workspace crates

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/simulation/src/client.rs	Replaced LruCache with IndexMap for storing SET statements, simplified iterator implementation
src/tests/simulation/Cargo.toml	Replaced lru dependency with indexmap
src/stream/src/executor/temporal_join.rs	Updated hasher import from lru::DefaultHasher to risingwave_common::lru::RandomState
src/stream/Cargo.toml	Removed lru dependency from stream crate
src/meta/Cargo.toml	Updated indexmap to use workspace version
src/connector/Cargo.toml	Updated indexmap to use workspace version
src/common/Cargo.toml	Moved lru dependency from main dependencies to dev-dependencies
Cargo.toml	Defined indexmap workspace dependency with version 2 and serde feature

[wenym1]

May merge after #23473